The invention relates to a method for roaming management in a mobile radio unit whose memory stores multiple different, individually activable identity profiles that include different access options for the mobile radio unit in respect of different mobile radio networks. In the method, the suitability of a currently active identity profile is automatically verified according to prescribed rules and taking into account a current position of the mobile radio unit, and a decision is made as to whether to switch to a currently inactive identity profile.
The invention further relates to an infotainment system for a motor vehicle, comprising                a mobile radio unit as transmission and reception unit, whose memory stores multiple different, individually activable identity profiles that includes different access options for the mobile radio unit in respect of different mobile radio networks,        a navigation unit that is functionally coupled to the mobile radio unit,        a control unit that is functionally coupled to the mobile radio unit and to the navigation unit and that is set up to use automation based on prescribed rules and taking account of a current position of the mobile radio unit to check a suitability of a currently active identity profile and to make a decision about switching to a currently inactive identity profile.        
Finally, the invention relates to a motor vehicle that is equipped with an infotainment system of this kind.
Roaming management methods of the type in question are known from WO 2011/161490 A1. This document discloses mobile radio units equipped with a SIM card (SIM: subscriber identification module). In this case, the SIM card has two identity profiles between which it is possible to change as required. According to current mobile radio standards, a SIM card stores a plurality of files that contain operator- and user-specific data and also data about mobile radio networks that are currently available. These files are read and/or edited when the mobile radio unit interacts with mobile radio networks. Particular importance is held by what is known as roaming, which involves a user transporting his mobile radio unit into regions outside the coverage area of his home network operator. In order to be able to use mobile radio services therein, he needs to dial up into networks of extraneous operators, the nature and scope and also costs of the services used being dependent on specific agreements between the home network operator and the operator of those networks that are currently being used. In order to prevent the user from using inadequate and/or overpriced services in a network with whose operator the home network operator has no or inadequate agreements while a better supply of services at cheaper prices can be used in another mobile radio network that is likewise available, there is a need for management that measures up to the respective outline of the individual case. Such a management method is normally performed in automated fashion, since manual management by the user would require the latter to have detailed knowledge of existing agreements.
In the aforementioned document, the SIM card stores two identity profiles for the user, namely a home profile and a roaming profile. The home profile is used for handling service use in the home network; the roaming profile is used for handling service use in extraneous networks. As an essential component of each profile, current mobile radio standards define what is known as the IMSI (international mobile subscriber identity). The IMSI here is a unifocal subscriber identifier and is associated with a mobile radio operator having a country identifier (MCC: mobile country code) and a mobile radio operator identifier (MNC: mobile network code).
Roaming management involves the respective current position of the mobile radio unit being ascertained. This can be accomplished by use of satellite-controlled position finding (e.g. GPS) or in interaction with elements of a land-based mobile radio network. On the basis of the determined position, a control unit coupled to the mobile radio unit uses prescribed rules to compute which of the stored IMSIs needs to be activated each time in order to be able to use required mobile radio services in optimum fashion, this being dependent particularly on the specific dialup into one of the mobile radio networks available at the ascertained position. This system has disadvantages in cases in which the user is located in a border region between the networks of different operators. This can give rise to the rules for selecting the appropriate IMSI, which are essentially focused on the current position, leading to quickly alternating changeover between the IMSIs. This is the case particularly with fast-moving mobile radio units, for example with mobile radio units that are used as an interface for an infotainment system in a motor vehicle. In many cases, an IMSI change leads to at least temporary connection interruption, for the most part at any rate at least to changes in the currently available services.
The object of the present invention is to provide a roaming management method that leads to fewer disconnections even in border regions.
A further object of the invention is to provide an appropriate infotainment system for motor vehicles.
The first-mentioned object is achieved by a method for roaming management in a mobile radio unit whose memory stores multiple different, individually activable identity profiles that comprise different access options for the mobile radio unit in respect of different mobile radio networks, wherein automation based on prescribed rules and taking account of a current position of the mobile radio unit is used to check a suitability of a currently active identity profile and to make a decision about switching to a currently inactive identity profile. The decision about the change of profile additionally takes account of an estimated movement destination for the mobile radio unit.
The second-mentioned objects is further achieved by an infotainment system for a motor vehicle, comprising a mobile radio unit as transmission and reception unit, whose memory stores multiple different, individually activable identity profiles that comprise different access options for the mobile radio unit in respect of different mobile radio networks, a navigation unit that is functionally coupled to the mobile radio unit, and a control unit that is functionally coupled to the mobile radio unit and to the navigation unit and that is set up to use automation based on prescribed rules and taking account of a current position of the mobile radio unit to check a suitability of a currently active identity profile and to make a decision about switching to a currently inactive identity profile. The control unit is further set up to additionally take account of an estimated movement destination for the mobile radio unit in the decision about the change of profile, which movement destination is retrievable from the navigation unit.
An aspect of the invention is that not only a current position of the mobile radio unit but also, in addition, a movement destination for the mobile radio unit, which is ascertained by estimation, is taken into account when a decision about a possible change of identity profile needs to be made in an automated fashion. The result of this is that even in cases in which a change of profile on the basis of the current position would lead to currently cheaper service use, a change of profile that is possibly linked to disconnection can be avoided in view of the fact that the mobile radio unit will, in all probability, shortly be again located at a position at which the current profile will deliver better performance than the currently optimum profile. In this respect, the method according to the invention can be used to temporarily tolerate less than optimum service use, which is significantly overcompensated for, in terms of overall performance, by the advantage of disconnection being avoided, however. Only in cases in which it becomes clear from the estimated movement destination that the currently optimum profile would also have advantages over alternatives in the longer term is a change of profile initiated and disconnection tolerated. Overall, this allows minimization of the number of disconnections that are inconvenient for the user and of the costs for services that are used.
In one preferred embodiment of the invention, a navigation destination that is active in a navigation unit functionally coupled to the mobile radio unit is used as the estimated movement destination. In other words, the estimation, according to the invention, of the movement destination is effected on the basis of an explicit input into a navigation unit. In this connection, it should be pointed out that terms such as mobile radio unit, control unit, navigation unit, etc., are always intended to be understood in the present context in purely functional terms and not necessarily in design terms. In particular, components that contain functional mobile radio, control and navigation units, etc., in a common components are contemplated. However, it is naturally also possible for different components to be functionally coupled. Both variants are intended to be covered by the present invention.
Alternatively, a probable movement destination can be used as the estimated movement destination, wherein the probable movement destination used is a movement destination that is selected based on prescribed rules using current movement circumstance parameters from a database that comprises earlier movement destinations for the mobile radio unit together with the associated movement circumstance parameters thereof. By way of example, such a database contains an association for earlier movement destinations with starting times, calendar dates, starting directions of travel, etc. Routes that are frequently traveled at the same times of day, such as a distance between the home and the workplace, for example, therefore result in high entry numbers in the database. If current journey circumstance parameters are akin to frequently stored journey circumstance parameters, there is a high degree of probability that the same movement destination is also valid. In accordance with the explained embodiment of the invention, this probable movement destination is used as the estimated movement destination, which influences the current decision by means of a change of profile.
In one preferred embodiment of the invention, the mobile radio unit is a transmission and reception unit of an infotainment system in a motor vehicle. Modern motor vehicles are equipped with complex systems for entertainment and obtaining information, for example about traffic situations, news, etc. The relevant data flow via a mobile radio unit in the motor vehicle and via devices interacting with said mobile radio unit in land-based mobile radio networks. As already mentioned at the outset, efficient roaming management is of particular importance particularly in fast-moving mobile radio units. The cited mobile radio units of infotainment systems in motor vehicles are particularly affected thereby.
Favorably, the memory containing the identity profiles includes a SIM card that stores a plurality of IMSIs that each represent an identity profile. This approach follows the approach of storing multiple IMSIs on a SIM card that is known from the prior art. Alternatively, provision may also be made for the memory containing the identity profiles to include a plurality of SIM cards that each store an IMSI representing an identity profile. This variant has advantages in view of upgradeability and expandability of the system.
The current position of the mobile radio unit, which continues to be necessary for efficient roaming management, is preferably determined by involving satellite-assisted position finding by means of a position finding unit that is functionally coupled to the mobile radio unit. Typically, such a position finding unit is connected to the worldwide GPS system and is part of an ordinary navigation system.
Alternatively or additionally, provision may be made for the current position of the mobile radio unit to be determined by involving position-related data from network equipment elements that interchange data with the mobile radio unit. Land-based mobile radio networks are known to be comparatively small-celled, which means that the current position of the mobile radio unit can be determined from the data interchanged with a mobile radio unit in the course of a specific interaction and/or by way of signal strength comparison for signals from different transmission stations.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.